| Geyser | 1981-08-31 |
|---|---|
| Arsenic | 1229 |
| Echinus | 1403:40, 1554:54 |
| Fan and Mortar | 1030 |
| Morning | 1111, 2250 |
| Splutter Pot | 1800 |
| UNNG-NBK-8 | 1200 |
| Whirligig | 1747 |
| Values for Old Faithful Area | 1981-08-31 |
|---|---|
| Astronomical Twilight Begin | 05:00 |
| Nautical Twilight Begin | 05:38 |
| Civil Twilight Begin | 06:15 |
| Sunrise | 06:45 |
| Sunset | 20:01 |
| Civil Twilight End | 20:31 |
| Nautical Twilight End | 21:08 |
| Astronomical Twilight End | 21:46 |
| Moon Illumination | 2.95% |